Heretofore, it has been known to produce normal bias ply and radial tires with fabric or steel belts incorporated therein, which belts are designed to make the tread run flatter and give better road contact, and which belts also are alleged to increase the overall life-wearing characteristics of the tire.
However, these belts are always of bias, ply-type construction, and therefore do not completely control radial force variations in the tire, which force variations lead to a bumpy and uneven ride in the vehicle upon which the tire is mounted. Force variations have become an increasing problem in radial tires because of the much longer and heavier treads thereof, and further because these tires have a larger overall footprint configuration where the tire meets the road and, hence, tend to have more susceptibility to radial force variations. It is further believed more difficult to control the exact circular or circumferential nature of the radial tires, and it is this factor which I believe leads to increased difficulty with such force variations in radial tires.
It has further been a problem in retreaded bias or radial tires having the fabric or steel belts incorporated therein, that a delamination occurs at the lateral edges of the belts with respect to the retreaded portion, thereby making the retread ineffective and substantially cutting the life of the retread. Such delaminations also occur in radial tires, particularly at the lateral edges of the belts even in new tires, because of a weakened area occurring in the radial tire at these areas due to greater flexing, and the fact that the outer tread rubber cannot adhere through these lateral edges because of the greater flexing during the running of this tire.
It should be understood that the instant invention represents an improvement over the siping arrangement and belt procedure of my own prior U.S. Pat. No. 4,040,464 that issued on Aug. 9, 1977, wherein the siping material actually forms a reinforcing belt right at the base of the tread design which I have found does not give as good a reinforcing ability as when this belt is positioned between the bottom of the tread design and the belts in the tire, as shown in my FIGS. 1 through 3 herein. This is partially because the siping material is not vulcanized to rubber tread. In addition, the siping arrangement did not extend over the lateral edges of the belt plies and, hence, the delamination problem at that point was not solved.